710 GEORGE W. STOSE 



fossiliferous thin-bedded limestones with argillaceous partings. It 

 varies in thickness across the strike from a maximum of 600 feet 

 in the Chambersburg belt to about 100 feet in the McConnellsburg 

 Cove. 



Its most typical development is in the Chambersburg belt through- 

 out which fossils are abundant. The following section in the railroad 

 cut 1 1 miles west of Kauffman is the most complete continuous section 

 in this belt. 



Feet 



Black shale (Martinsburg) 



Largely concealed, but probably chiefly shale (near the top are black carbon- 

 aceous limestone with conchoidal fracture, shaly dark crystalHne 

 limestone, thin sandstone, and 10 feet of coarse crystalline limestone 



containing Lingulas) 150 



Calcareous shale and limestone 100 



Nodular clayey limestone 50 



Dark platy limestone ^ . . . 94 



Compact dark limestone, very fossiliferous 108 



Cobbly limestone containing numerous Nidulites, bryozoa, and a layer of 



cystid heads 105 



Total 607 



The "cobbly" character of the weathered outcrop of certain of 

 the beds, due to a wavy lammation or clay parting that crosses the 

 bedding at a high angle and, on weathering, gives rise to rounded 

 lenticular masses resembling rough cobbles, 's one of the noticeable 

 features of this formation. The upper 200 feet of the formation is 

 composed largely of shale with interbedded thin fossiliferous lime- 

 stones. 



In the Welsh Run-Eden ville belt, 2^ miles southeast of Mercers- 

 burg, the following section occurs on the banks of West Branch of 

 Conococheague Creek. 



Feet 



Fissile shale containing graptolites and \ 



lingulas / 



Calcareous black shale and hard thin ; Martinsburg shale. 



black carbonaceous limestones, 80 \ 



feet. / 



Granocrystalline limestone, fossiliferous 2 



Cobbly dark subcrystalline limestone, both massive and thin-bedded ... 73 

 Coarse massive granocrystalHne limestone with massive beds of pure fine- 

 grained limestone 75 



